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EVALUATING TEAR FILM QUALITY WITH A DOUBLE-PASS BASED SCATTERING INDEX. Pablo Artal, Guillermo M. Pérez, María Fernández, Sandra Mirabet*, José M. Marín*. L ABORATORIO DE O PTICA, U NIVERSIDAD DE M URCIA , SPAIN * Hospital Virgen de la Arrixaca, Murcia, SPAIN. Supported by:.
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EVALUATING TEAR FILM QUALITY WITH A DOUBLE-PASS BASED SCATTERING INDEX Pablo Artal, Guillermo M. Pérez, María Fernández, Sandra Mirabet*, José M. Marín* LABORATORIODEOPTICA, UNIVERSIDAD DEMURCIA, SPAIN * Hospital Virgen de la Arrixaca, Murcia, SPAIN Supported by:
The quality of the tear film affects the retinal image and visual performance Double-pass retinal image ...the dynamic analysis of the double-pass retinal images may provide objective information on tear film quality
Methods (I) Dynamic recording & analysis of Double-Pass (DP) retinal images1 Scheme of the DP method Input Beam Double-pass (DP) retinal image Entrance Pupil DP Image Exit Pupil OSI Beam Splitter An Objective Scatter Index (OSI), estimated from the double pass images, quantifies scattering. Changes in scattering over time are related to tear film. OQAS Instrument (Visiometrics SL) 1. Santamaría, Artal & Bescós., J.Opt. Soc. Am. A., 1987
Methods (II) DP Image Patients 6 Healthy Eyes Age = 28 ± 5 8 Dry Eyes Age = 48 ± 11 Series of DP images recorded with an OQAS Instrument (Visiometrics SL) Processing the DP images - The OSI parameter was computed for every DP image of the series • Every series was characterized by an average value of OSI and its corresponding standard deviation - Defocus and astigmatism were previously corrected - Series of DP images were registered during 30 seconds - Different break-up cycles were recorded in every series
Results (I) Temporal evolution of the DP images for normal and dry eyes Healthy Eye Normal break-up cycles Healthy Eye Accelerated break-up cycles Dry Eye
Results (II) Objective scatter index (OSI) as a function of time OSI Healthy Eyes Normal break-up cycles time (s)
Results (II) Objective scatter index (OSI) as a function of time OSI Healthy Eyes Accelerated break-up cycles Healthy Eyes Normal break-up cycles time (s)
Results (II) Objective scatter index (OSI) as a function of time Dry Eyes OSI Healthy Eyes Accelerated break-up cycles Healthy Eyes Normal break-up cycles time (s)
Results (III) Average objective scatter index (OSI) for every eye tested Dry Eyes OSI = 3 ± 2 Healthy Eyes Normal break-up cycles OSI = 0.5 ± 0.1 Healthy Eyes Accelerated break-up cycles OSI = 0.9 ± 0.3
Results (III) Standard deviation of the objective scatter index (OSI) for every eye tested Healthy Eyes Normal break-up cycles SD_OSI = 0.08 ± 0.03 Dry Eyes SD_OSI = 0.6 ± 0.4 Healthy Eyes Accelerated break-up cycles SD_OSI = 0.3 ± 0.1
Results (III) Average objective scatter index (OSI) for every eye tested OSI is larger and more variable in dry eye’s patients! Dry Eyes OSI = 3 ± 2 Healthy Eyes Normal break-up cycles OSI = 0.5 ± 0.1 Healthy Eyes Accelerated break-up cycles OSI = 0.9 ± 0.3
Conclusions i) A novel robust and objective method to measure the optical quality of tear film has been developed based on measuring the induced changes of ocular scatter estimated from double-pass images. ii) This technique may be useful to detect and follow-up tear-film related patient’s complaints more accurately than with current approaches.